Structural model splicing method based on well seismic combination

The use of small blocks with model-building results for overall structural model splicing can unify fault understanding, effectively integrate existing small block model results, and form a unified and continuous overall model. This article focuses on the structural models of two small blocks in the central and western parts of a certain area, and studies the method of splicing structural models at the sedimentary unit level to lay the foundation for the precise tapping of the potential of the fault edge.

Study of Reasonable Length of Coal Seam Mining under Different Fault Dips

In this paper, the stress and strain distribution in coal seam and fault edge under various fault dips is numerically simulated to study the stability of the barrier pillar and determine the reasonable length of coal seam mining using COMSOL Multiphysics package. Numerical simulations show that remarkable increase in stress around fault edge when coal seam is about 250 m away from the fault with a smaller fault angle and the stability of fault is seriously affected by the mining excavation. While the obvious increase in stress around fault edge can be observed until coal seam is about 200 m or 150 m away from the fault with a larger fault angle and the stability of fault is seriously affected by mining excavation. Numerical results indicate that the larger the fault dip is, the larger the reasonable mining length in coal seam where a fault near coal seam exists. Moreover, the fault with smaller dip is more easily activated to induce the failure of the fault and the occurrence of water inrush in coal mining. To prevent the occurrence of fault failure accident, we need to study the reasonable mining length of coal seam, to ensure the safety production and increase the recovery ratio of coal.

Distribution Characteristics of the Remaining Oil of Putaohua Oil Layer in Pubei Oil Field of Songliao Basin

A comprehensive analysis has been made for the remaining oil of Putaohua oil layer in Pubei oil field of Songliao basin by using core and logging and dynamic data. It is considered that it’s distribution is controlled by positive structures, lateral fault seal, sedimentary microfacies and pattern matching of ‘fault-sand’. The forward fault trap and the top of internal micro-structures on the edge of fault block control the position of the enrichment of remaining oil; lateral fault seal affects the level of the enrichment of the remaining oil; the underwater distributary channel of shallow water delta and the main sheet sand constitute the remaining oil reservoir unit; pattern matching of fault and sand determines the rich layer of remaining oil. On the basis of the above study, four types of remaining oil has been established: fault edge screened type, top of micro-structures type, injection-production imperfection type and anisotropism of sheet sand. Different programs for different situations are proposed: inclined well for fault edge screened type, infilled straight well for top of micro-structures type, horizontal well for injection-production imperfection type, well fracturing for anisotropism sheet sand.

Radiation from a realistic model of faulting

abstract The Knopoff-deHoop representation theorem has been used to calculate the form of the body waves radiated from an elliptical fault. Rupture is assumed to initiate at one focus of the ellipse and then spread out radially on the fault plane. Two cases are considered: 1) constant slip everywhere on the fault surface and 2) a variable slip which approaches zero at the fault edge. The radiation is calculated for distances from the fault which are large compared to the fault dimensions. The body waves are described by the product of two factors, one of which is the familiar equivalent-force system radiation pattern. The other factor includes the time dependence of the signal; it does not depend upon the direction of slip. The body waves exhibit two stopping phases. The theory is used to estimate the fault dimensions associated with six deep-focus earthquakes studied by Kasahara. The estimated fault dimensions are about twice the dimensions of the focal sphere as found by Kasahara. Finally, the difference between the phase spectrums of shallow and deep-focus earthquake radiation observed by Kishimoto is shown to be related to a difference in shape of the two fault surfaces; shallow-focus earthquakes appear to be associated with elongated fault surfaces, whereas deep-focus earthquakes are associated with more circular fault surfaces.